This invention relates to a fuel delivery system heater, and particularly, to an apparatus and method for warming the fittings and fuel within a fuel line of a diesel powered motor vehicle which connects the fuel tank to a fuel processor.
Diesel powered apparatus such as motor vehicles are often operated in environmental conditions wherein the fuel oil and fuel delivery circuit are subjected to cold ambient temperatures. At sufficiently low temperatures, fuel oil can cloud, becoming viscous and actually develop solid wax particles. In addition, water, a common fuel contaminate, can accumulate as solid ice deposits. These conditions severely restrict fuel flow within the fuel delivery lines. In order to address such problems, many users of diesel powered apparatus provide a fuel processor within the fuel delivery system. a number of such devices are described by my previously issued U.S. Pat. Nos. 4,368,716; 4,428,351; 4,395,996; 4,421,090 and pending patent applications, Ser. Nos.: 463,041, filed Feb. 1, 1983; and 573,292, filed Jan. 23, 1984. Many of the fuel processors described by the preceding patents and patent applications further provide a water separting and particulate filtration function. Since these fuel processors are typically mounted some distance from the fuel tank, however, fuel within the lines connecting the fuel tank and fuel processor are not subjected to the heating effect provided by the fuel processor. These lines are therefore subject to fuel line restrictions caused by cold temperatures. Particular problems have been encountered in the field with fuel flow restrictions developing at the fuel line elbow fitting connected to the fuel tank.
It is an object of this invention to provide an apparatus and method which acts to warm fuel in the fuel line connecting a fuel tank to a fuel processor device. It is a further object of this invention to enable modulation of the warming effect of the fuel in the fuel line to prevent warming in conditions where it is unnecessary.
The above principal objects of this invention are achieved by employing a pair of improved fuel connection fittings, each having three ports communicating with an interior chamber. One of such fittings is connected to the fuel tank and another to the fuel processor outlet. Two of the remaining ports of the fittings are employed to conduct fuel in the normal flow path. The third ports, however, are employed to remove a portion of the warmed fuel exiting from the fitting at the fuel processor and circulates the fuel to the fitting connected to the fuel tank. Such flow is caused by the action of an inline fuel pump, preferably of an electrically powered variety. A portion of the warmed fuel, therefore, is mixed with cold fuel being drawn from the fuel tank, thereby increasing its combined temperature. Such increased fuel temperature reduces the likelihood of restrictions within the fuel line fittings and through the fuel line itself cause by low fuel temperature.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.